interface StudentInterface {
    uname: string
    age: number
    sayHi: ()=>void
}

class Student implements StudentInterface {
    uname:string=''
    age:number=0
    // constructor(uname:string) {
    //     this.uname=uname
    // }
    sayHi() {}

    //Student实现某个接口，就必须包含接口所拥有的属性和方法，也可以又其他属性方法
    sing() {}
}